The function of detecting a broken glass substrate in an LC display panel(“Display Glass Broken Detect function”) has been described in Japanese Unexamined Patent Application Publication No. JP-A-2012-220792. According to JP-A-2012-220792, a disconnection-detecting metal line is formed around a glass substrate (thin-film transistor (TFT) substrate) of an LC display panel having an LC display part formed in a center portion thereof. The disconnection of the disconnection-detecting metal line can be detected by checking the electrical continuity of the metal line through a pair of external terminals to which the metal line is connected during a manufacturing process. In case that the disconnection is detected, a crack reaching an LC display region is regarded as being formed in the glass substrate. In the case of an LC display driver supporting the detection of disconnection by use of a disconnection-detecting metal line as described above, the LC display driver outputs a predetermined voltage signal to the disconnection-detecting metal line, accepts the input of a voltage signal fed back through the disconnection-detecting metal line, and uses a comparator to make determination on whether or not a difference equal to or larger than an allowable voltage is caused between the voltage signals. On condition that the difference remains equal to or larger than the allowable voltage for a fixed period of time, the LC display driver determines that disconnection has occurred, i.e., a crack is formed.